Compact dumbbell



FIG. 1 is a perspective view of a compact dumbbell, showing my new design;

FIG. 2 is a view in side elevation;

FIG. 3 is a top plan view;

FIG. 4 is a bottom plan view;

FIG. 5 is a view in end elevation from left to right as viewed in FIGS. 1 and 2; and,

FIG. 6 is an end view from the end opposite FIG. 5. 

The ornamental design for a compact dumbbell, as shown and described. 